When manufacturing printed circuits and printed circuit boards, there is a fundamental distinction between the widespread subtractive technique, that proceeds on the basis of metal-laminated substrates or base materials and that removes copper not required for conductor tracks by etching, and the additive technique, that proceeds on the basis of adhesive-coated substrates and that applies the interconnect material from baths only to where conductor tracks are required. Combinations of these methods are also known. In all versions, the actual conductive pattern is photolithographically produced by applying, exposing and developing photoresist layers. In traditional light-sensitive photoresist layers, which can be a matter of plating resists or etch resists dependent on the technique employed, the application of the liquid resist material occurs by immersion, roll-on or whirl coating. However, it is also possible to laminate the resist material onto the substrate in the form of what is referred to as a dry film resist using a suitable gluing means.
German reference DE-A-36 28 340 discloses a method for manufacturing printed circuit boards having the desired conductive tracks using a light-sensitive resist film applied on a surface of a copper-plated, insulating substrate. In this method the lightsensitive resist film is electro-deposited onto the surface of the copper-plated substrate by immersing the insulated substrate in a lacquer deposition bath containing, as a main constituent, watersoluble plastics or plastics dispersed in water that cure under the action of light. The structurable resist is electrophoretically applied, whereby such an application is also often referred to as anodic or cathodic electro-dipcoating when used in industrialscale lacquering. The electrophoretic application of the light sensitive resist film occurs in a container that accepts the lacquer deposition bath into which the printed circuit board to be coated and two plate-shaped electrodes, that are spaced from the printed circuit board, are suspended from above the container.
European reference EP-A-0 370 133 discloses that solder resists can be electrophoretically applied onto printed circuit boards in addition to etch resists and plating resists.
In industrial fabrication of printed circuit boards, the electrical application of a lacquer serving as an etch resist, plating resist or solder resist must be capable of being performed in a continuous operation, whereby what are referred to as horizontal continuous-flow systems enable an especially economical employment in the present case as well as in the case of the corresponding electroplating devices. However, known electroplating devices for printed circuit boards fashioned as horizontal continuous-flow systems (see European reference EP-A-0 254 962 or German reference DE-A-36 24 481) cannot be used for the electrophoretic application of a lacquer. This is because, by contrast to voltaically deposited metal layers, the electrophoretically deposited lacquer layers have a high specific resistance and, due to their unavoidable deposition onto the circulating contact elements, prevent a reliable contacting of the printed circuit boards after a short time.